The invention relates to coal-burning utility electrical power generation plants, and more particularly to a clinker grinder seal and valve.
In a coal-burning utility electrical power generation plant, coal is pulverized in a ball tube mill and supplied as coal dust to a burner for ignition and combustion with incoming combustion air. After ignition and burning, the spent coal dust fuses as hardened chunks, called clinkers, which are collected and ground at a lower clinker grinder, for discharge and disposal. The clinker grinder includes a grinding chamber with a plurality of grinding teeth on plates mounted to a rotary shaft supported for rotation by external bearings on each side of the grinding chamber. Between the grinding chamber and each bearing is a seal cage having a packing or stuffing box through which the rotary shaft extends. The seal cage and packing box seals the interior of the grinding chamber, to minimize escape of coal dust or particles.
The present invention provides improvements in the clinker grinder seal cage. In one aspect, a one-way seal is provided permitting flushing fluid flow from a flushing fitting into the grinding chamber, and blocking reverse flow. In another aspect, improvements in the stuffing box provide longer life.